The engine stalls at idle?

Has the check engine light come on? It sounds like a vacuum leak or the IAC is bad. These guide will help us find out the problem

https://www.2carpros.com/articles/stall-at-idle

and

https://www.2carpros.com/articles/checking-a-service-engine-soon-or-check-engine-light-on-or-flashing

and

https://www.2carpros.com/articles/how-to-replace-an-idle-speed-control-motor-iac

Please run down these guides and report back.

Good to hear, please use 2CarPros anytime we are here to help.

A lean mixture can also identify a vacuum leak. Have you checked for that?

Is the MAF getting clogged with dirt? If so, is the air filter good? Also, there are several vacuum hoses that are on and around the engine. I would recommend checking for any broken, disconnected, or dry rotted ones.

As far as the MAF getting dirty, do you live in an area where there is a lot of dust and dirt?

Have you ever noticed any oily substances on the air filter or in the intake where the MAF is located? Have you ever replaced the EGR valve? I'm starting to think the engine may have blow-by and allowing oily air from the engine is making it way through the PCV and into the maf.

Let me know. Here is a little check. With the engine running, open the oil fill cap and see if there is a lot of pressure coming out of it.

Let me know what you find.
Joe

Chad, The EGR valve won't cause a code. It should be part of a tune up. As far as checking if there is a lot of pressure coming from the oil cap when opened, that will tell me if there is excessive blow-by. What causes that is worn piston rings. When the piston builds compression, bad rings allow compression to escape into the crank case. If that is the problem (which would be odd at this mileage), the only thing you can do is replace the rings.

Let me know what you find.

Hi,

The component that maintains idle speed is called an idle air control valve. It is located on the throttle body. If this isn't working properly, it could cause the engine to stall.

Here is a link that explains how to service one. Take a look through this and see if it is something you could do. If so, when the IAC is off the vehicle, inspect where it mounts for carbon build up and dirt. Also, see if the pintle on it moves a bit when the key is turned on and off. ( you will need a helper to do that)

https://www.2carpros.com/articles/idle-air-control-valve-service

Here is a link that shows in general how one is replaced:

https://www.2carpros.com/articles/how-to-replace-an-idle-speed-control-motor-iac

Now, if you confirm that it isn't working, here are the directions specific to your vehicle for replacement:

_______________________________________

1998 Ford Truck Explorer 4WD V6-245 4.0L SOHC VIN E EFI
Removal and Replacement
Vehicle Powertrain Management Fuel Delivery and Air Induction Idle Speed/Throttle Actuator - Electronic Service and Repair Removal and Replacement
REMOVAL AND REPLACEMENT
REMOVAL

Typical Idle Air Control Valve

Pic 1

1. Disconnect the Idle Air Control (IAC) valve electrical connector.

pic 2

2. Remove the IAC valve.
1 Remove the two bolts.
2 Remove the IAC valve.
- Discard the gasket.

pic 3

INSTALLATION

NOTE: Install a new IAC valve gasket.

1. Install the idle air control valve.
1 Position the IAC valve.
2 Install the two bolts.
3 Connect the IAC electrical connector.

_____________________________________

Let me know if this helps. Also, let me know if the engine has a rough idle at all times.

Take care,
Joe

I need to know if the check engine light is on? If it is then call around to your local parts stores and see if one does a free scan. Have them scan it and write down what codes are found then have them clear them. Get back to me with what you find. If the engine light is not on then we will go from there.

Ok if the check engine light is on then call around and find out if one of your local parts store will do a free scan and get back to me with what codes are there. Have them clear the codes after you get it scanned and write the codes down. Get back to me with the codes so we can try to see what the truck is telling us is wrong, and we will go from there.